Branch History Rolling Buffer (BHRB) is a new PMU feaure in IBM
POWER8 processor which records the branch instructions inside the execution
pipeline. This patchset enables the basic functionality of the feature through
generic perf branch stack sampling framework.
Sample output
-------------
$./perf record -b top
$./perf report
Overhead Command Source Shared Object Source Symbol
Target Shared Object Target Symbol
# ........ ....... ....................
...................................... ....................
...................................
#
7.82% top libc-2.11.2.so [k] _IO_vfscanf
libc-2.11.2.so [k] _IO_vfscanf
6.17% top libc-2.11.2.so [k] _IO_vfscanf
[unknown] [k] 00000000
2.37% top [unknown] [k] 0xf7aafb30
[unknown] [k] 00000000
1.80% top [unknown] [k] 0x0fe07978
libc-2.11.2.so [k] _IO_vfscanf
1.60% top libc-2.11.2.so [k] _IO_vfscanf
[kernel.kallsyms] [k] .do_task_stat
1.20% top [kernel.kallsyms] [k] .do_task_stat
[kernel.kallsyms] [k] .do_task_stat
1.02% top libc-2.11.2.so [k] vfprintf
libc-2.11.2.so [k] vfprintf
0.92% top top [k] _init
[unknown] [k] 0x0fe037f4
Changes in V2
--------------
- Added copyright messages to the newly created files
- Modified couple of commit messages
Changes in V3
-------------
- Incorporated review comments from Segher https://lkml.org/lkml/2013/4/16/350
- Worked on a solution for review comment from Michael Ellerman
https://lkml.org/lkml/2013/4/17/548
- Could not move updated cpu_hw_events structure from core-book3s.c
file into perf_event_server.h
Because perf_event_server.h is pulled in first inside
linux/perf_event.h before the definition of
perf_branch_entry structure. Thats the reason why perf_branch_entry
definition is not available
inside perf_event_server.h where we define the array inside
cpu_hw_events structure.
- Finally have pulled in the code from perf_event_bhrb.c into
core-book3s.c
- Improved documentation for the patchset
Anshuman Khandual (5):
powerpc, perf: Add new BHRB related instructions for POWER8
powerpc, perf: Add basic assembly code to read BHRB entries on POWER8
powerpc, perf: Add new BHRB related generic functions, data and flags
powerpc, perf: Define BHRB generic functions, data and flags for POWER8
powerpc, perf: Enable branch stack sampling framework
arch/powerpc/include/asm/perf_event_server.h | 7 ++
arch/powerpc/include/asm/ppc-opcode.h | 7 ++
arch/powerpc/perf/Makefile | 2 +-
arch/powerpc/perf/bhrb.S | 44 +++++++
arch/powerpc/perf/core-book3s.c | 167 ++++++++++++++++++++++++++-
arch/powerpc/perf/power8-pmu.c | 57 ++++++++-
6 files changed, 279 insertions(+), 5 deletions(-)
create mode 100644 arch/powerpc/perf/bhrb.S
--
1.7.11.7
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